EVIDENCE FOR A SQUARE-SQUARE VORTEX-LATTICE TRANSITION IN A HIGH-Tc CUPRATE SUPERCONDUCTOR
J. Chang, Zürich University, M. Ichioka, Okayama University, D. Campbell, D. Le Boeuf, LNCMI Grenoble. In the physics of correlated electron systems, van Hove singularities play a key role. These are points in the band structure where the density of states is singular. When the Fermi level is tuned towards [...]